It would be interesting to see more photos of 'legible' crates, that once 'housed' U.S. Krags, for storage and shipping. Some may be a source of useful information.

Frank Mallory provided one in "KRS" that had a wealth of data.
I think, I have a plausible explanation of what the initials meant.

(My take, FWIW):

"With Front-Sight & Muzzle Covers
(case #) 10289
20 Magazine Rifles Cal .30,
Mod. (18)98 with (19)02 Rifle Sights with Peep Aperture
Eye Piece Model (18)98 Altered for Serrature
20 Oilers 4 Screwdrivers
Manufactured Dec. 1899
Oiled with Cosmic (preservative oil)
Repacked Feb. 1905"

The 'boxed' model 1898 rifles were likely accompanied with accessories and the 1902 sight variation, as shown in attached photos.

(With all the Krag rear-sight saga & 'musical chairs', some of the story may be documented by stencils on crates).

The above crate is marked as containing 20 model 1898
magazine rifles, that were manufactured in December, 1899.

Certain things can be inferred regarding these Krags:

The twenty rifles were likely serial numbered around 238673 to 243660, (William Mook's estimated figures for December 1899), or 239901 and 240101, (Joe Poyer's questionable figures, which only allow 200 rifles for December).

Being manufactured in this period makes it likely that these rifles had the model 1898 'Dickson' sight and the "head-less" cocking-piece, when first packed into the crate.

When the rifles were "repacked in February 1905", it is likely the rear-sights were switched to 1902 sights.

It is fitting, if my interpretation is correct, that the replacement model 1902 sights, were the variation that used the 'recycled' 1898 sight-leaf.

Mallory wrote, that in 1902 and 1903, approximately 110,000 model 1898 rifle sights were converted to the 1902 sight pattern.